I ran across this usenet posting and since it seems likely that you missed it or don't have access to the usenet group itself, I asked the author, K. Krueger, if I could quote it.

The question being answered is "How does the pokéball work?"

To understand the works of a pokeball, we first must examine the basic elements common to all pokemon. Many things can be eliminated from this list - most are small, but the Snorlax is very large. Most only speak their own names, but Meowth has a functioning vocabulary. They are of varying temperments and environments.
The key element, therefore, is cuteness (kawaii). While some may debate that not all Pokémon are cute, the relative cuteness of the Pokémon to non-Pokémon consisting of similar traits is striking - even the Pokémon sludge monster is much cuter than an actual pile of sludge.
The Pokéball, then, works by emitting a dual wave of graviton and kawaii particles, entwined in a double helix formation. This beam latches on to the cuteness that is nearby, and creates a localized gravity well that proceeds to suck the Pokémon into the ball. When the entire Pokémon is inside, the well pulls the ball shut, and then collapses, leaving you with a trapped Pokémon. This process also correctly ionizes the Pokémon, making them both more tame and easier to return to the ball in future episodes.
One should be careful to not use Pokémon balls around kittens, young children, rainbows, fluffy white unicorns, and physicists.
-- Kirby Krueger O- kirbyk@best.com

© Copyright by Larry W. Virden <lvirden@yahoo.com>, 1999,2000,2001,2002,2003,2004,2005,2006 http://www.purl.org/net/lvirden/Pokemon/pokeball-1.html